08.05.2019 10:58, Mark Brown пишет: > On Sun, Apr 14, 2019 at 08:59:39PM +0300, Dmitry Osipenko wrote: >> Add regulators coupler for Tegra30 SoC's that performs voltage balancing >> of a coupled regulators and thus provides voltage scaling functionality. > > Same here, what are the requirements this is implementing? >
There are two coupled regulators: CPU and CORE. Constraints: 1) The max-spread voltage is 300mV. 2) CORE voltage must be higher than the CPU by at least N mV, where N varies depending on the CPU voltage. 3) There is a constraint on the maximum CORE voltage depending on hardware model/revision (cpu_speedo_id) where a higher voltages apparently may cause physical damage, so it's better to hardcode the limitation in the code rather than to rely on a board's device-tree description. This constraint is quite vaguely defined in the downstream kernel, I'm not really sure if it's solely about the hardware safety.
